The coverage, exemption and other provisions of the Act depend, in part, on the scope of the terms employer, establishment, or enterprise. As explained more fully in part 776 of this chapter, these terms are not synonymous. The term employer has been defined in the Act since its inception and has a well established meaning. As defined in section 3(d), it includes, with certain stated exceptions, any person acting directly or indirectly in the interest of an employer in relation to an employee. (See § 779.19.) The term establishment means a distinct physical place of business rather than an entire business or enterprise. (See § 779.23.) The term enterprise was not used in the Act prior to the 1961 amendments, but the careful definition and the legislative history of the 1961 and 1966 amendments provide guidance as to its meaning and application. As defined in the Act, the term enterprise is roughly descriptive of a business rather than of an establishment or of an employer although on occasion the three may coincide. The enterprise may consist of a single establishment (see § 779.204(a)) which may be operated by one or more employers; or it may be composed of a number of establishments which may be operated by one or more employers (see § 779.204(b)). The enterprise is not necessarily coextensive with the entire business activities of an employer; a single employer may operate more than one enterprise (see § 779.204(c)). The Act treats as separate enterprises different businesses which are unrelated to each other even if they are operated by the same employer.